Illuminated safety switch



Jan. 6, 1948. J, F, COURTNEY 2,434,065

ILLUMINATED SAFETY SWITCH Filed nec. 29, 1945 2 sheets-sheet '1 Jall- 6 1948. J. F. couRTNEY ILLUMINATED SAFETY SWITCH Filed Dec. 29, 1945 2 Sheets-Sheet 2 Patented Jan. 6, 1948 UNITED STATES PATENT OFFICE ILLUNINATED SAFETY SWITCH Joseph F. Courtney, Chicago, Ill. Application December 29, 1945, Serial No. 638,389 9 claims. (c1. zoo-'167) The present invention relates to illuminated safety switches, and is particularly concerned with actuating devices for electric switches, which are adapted to indicate the location of the actuating device in the dark, the on or 01T condition of the switch, and the condition of the circuit which the switch controls, such as, for example, an open circuit condition caused by failure of a lamp.

Another object of the invention is the provision of an improved electric switch structure of the class described, which is provided with an actuator that is suitably illuminated with a minute electric lamp, preferably of the type comprising a glow lamp, with spaced electrodes, which uses such a small amount of electric current that the expense of its operation for many thousand hours may be negligible, and which has such a high durability that it may be used for many thousand hours without replacement.

Another object of the invention is the provision of an improved electric switch structure of the class described having an illuminated actuator, and a mercury switch unit having the safety feature of being entirely hermetically closed so that there is no possibility of exposed sparking, which might ignite gas or cause explosions in some industrial locations.

Another object of the invention is the provision of an improved electric switch structure of the class described having an illuminated actuating member, which actuating member can be manufactured at a very low cost, so that it may be used on many electric switches already on the market, and the structure of which is very simple, so that its assembly or replacement involves a minimum amount of labor.

Another object of the invention is the provision of an illuminated actuating member for electric switches and the like, which may be constructed in various useful embodiments, in which the actuating member may be transparent, translucent, opaque with windows, or it may be translucent and provided in different colors, such as green or red or amber, as required in different installations, home, commercial, industrial, traic control, etc.

Another object of the invention is the provision of an improved electric switch structure of the class described, with an illuminated actuator which is resilient, which has a minimum of movclean and in good electrical conducting condition,

and the structure of which is sturdy and eiiicient throughout the several views.

Referring to the drawings, of which there are two sheets,

Fig. 1 is a front elevational view of a switch embodying the invention, with the wall plate removed and merely indicated in dot-dash lines;

Fig. 2 is a sectional view taken on the plane of the line 2-2 of Fig. 1, showing the detalls of structure of the switch assembly, with the wall plate attached and with the actuating member in side elevation;

Fig. 3 is an enlarged sectional view, taken on the piane of the line 3-5-3 of Fig. l, looking in the direction of the arrows, and showing the actuating member in cross section, but with the illuminating lamp, resistance, and other connections shown in elevation, assembled with a mercury switch member, which is illustrated in section;

Fig. 4 is a view in perspective of the lamp, re-

` sistor and connector assembly that is utilized in so that the assembly may be used for practically 55 Fig. 3;

Fig. 5 is a sectional view, taken on the plane of the line 5--5 of Fig. 3, looking in the direction oi' the arrows, illustrating the position of the lamp electrodes and of the various parts of the mercury switch;

Fig. 6 is an end elevational view of the actuating member, shown apart from the lamp and resistor; i

Fig. 'l is a fragmentary sectional View, taken on the plane of the line 1-1 of Fig. 5, looking in the direction of the arrows;

Fig. 8 is a wiring 4diagram of the preferred mode of use of the switch;

Fig. 9 is an alternative wiring diagram;

Fig. 10 is a sectional view, taken on the plane of the line IU-l D of Fig. 5, with the lamp removed;

Fig. 1I is a View similar to Fig. 9 of a modied form of construction; and

Fig. 12 is a fragmentary side elevational view of the projecting portion of the actuating member 60 for manual engagement in a modified form, when it is constructed of opaque or partially opaque material and provided with windows.

The present electric switch constitutes an improvement over that shown in U. S. Patent No. 2,142,153 to R. F. Sambleson, issued January 3, 1939; and it employs a mercury switch unit of similar construction to that shown in U. S. Patent 3 No. 2,101,093 to Payne, issued December '1, 1937.

This unit 20 is preferably enclosed in an insulating housing 2|, which may be constructed by molding out of a phenolic condensation product or some other suitable molded insulation.

The housing 2|, for example, is shown in full size in Fig. 2 and triple size in Fig. 5. It is provided with relatively thin side walls 22, 23 and integral bottom wall 24, as well as integral end walls 25, 26, the end walls being thickened in order to provide sockets for screw bolts, etc.

The shape of the housing may be varied, but the side walls 22, 23 are preferably parallel, and the bottom wall 24 is preferably partially cylindrical so as to require a minimum amount of material to occupy a minimum amount of space. The side walls 22 are suitably thickened near the bottom 24 so that they may be provided .with a pair of oppositely disposed partially cylindrical bearing surfaces 21, 28, which face toward thc front opening 29 of the housing and are adapted to be rotatably engaged by the cylindrical outer surfaces 30, 3| on the mercury switch unit 20.

The end walls 25, 26 are provided with suitable threaded bores 32, 33 opening on the face of the housing and adapted to receive the screw bolts 34, which fasten the switch assembly 35 to the housing 2|. The bores 32, 33 are located in the end walls, midway between the side walls.

The housing 2| also has its end Walls 25, 26 provided with the smooth cylindrical bores 36, 3'1 located in the diagonally opposite corners of the housing in the laterally extending cylindrical bosses 38, 39 (Fig. 1).

The bores 36, 31 are adapted to slidably receive the screw bolts 4U, 4| which form a part of the electrical connectors 42, 43 (Fig. 5) that establish a connection between line conductors and the mercury switch unit- 20. These connectors may be identical in construction, and each one may consist of an elongated at strip of metal, as shown in Fig. 2, the strip being provided at one end with a pressed, partially spherical formation 44 having an aperture 45.

At the other end each strip 42 or 43 is bent at right angles and provided with an attaching flange 46, which is located to lie on the face 41 of the end wall, and which is threaded to receive a screw bolt 40 or 4I.

Thus the conductor may be secured to the connector 42 or 43 by being passed around the screw bolt and being clamped between the head of the screw bolt 40 and the attaching flange 46.

The proportions of the parts of the connector 42 or 43 are such that when the attaching flange 46 lies fiat on the face 41 of the end wall 25 or 26, the partially spherical projection 44 is centered in a complementary depression 48 provided in the side of the switch unit 2D, when the switch unit 20 is resting with its cylindrical surfaces 30, 3| on the cylindrical bearing surfaces 21, 28 of the housing 2|.

Thus the mercury switch unit 20 is adapted to rotate against the surfaces 21, 28 of the housing, while still maintaining connection with the connectors 42, 43, which press resiliently against the sides of the mercury switch unit 20 in the spherical sockets 48.

The attaching flanges 46 are provided with a beveled engaging surface 49, which engages the edge of a slot at the surface 50 in the side wall 23 or 22, and thus tends to urge the spherical portion 44 of the connector inwardly toward the mercury switch unit 2|) to cause a resilient pressure against the side walls of the switch unit.

As the switch unit rotates, the contact surfaces 44 and 43 are constantly kept in a. bright and bare electrical contacting relation, to reduce contact resistance.

The connectors 42, 43 are held with their screw bolts 4U, 4| in the bores 36, 31 by suitable insulating barriers 5|, 52 (Fig. 2). Each barrier 5|, 52 comprises a flat plate or sheet of rigid insulating material, which is slidably held by guides for sliding movement into the opening 29 of the housing 2| at each end in such manner that a lower surface 53 on each barrier engages the attaching flange 46 on each connector 42, 43 to hold the bolts 4D, 4| in their bores 3G, 31.

The barriers themselves are held in place by a transverse frame member 54, which forms a part of the switch assembly 35, as will be further described. The mercury switch unit 20 comprises a centrally located partition 64 of porcelain, or other suitable refractory having electrical insulating properties. This ceramic partition 64 is surrounded by a toroidal bead of glass 65, and the partition supports a pair of sheet metal cupshaped members 66 and 61 of similar shape adapted to act as terminals for the mercury switch Iand as parts of the housing for the switch. y

The cup-shaped terminal members 66 and 61 may be substantially cylindrical, although they are preferably slightly tapered for convenience in stamping; and they are provided'with an out,- wardly turned flange 68 at the open end of each cup and with an inwardly extending partially spherical depression 49 located in the middle of the fiat end of each cup.

The cup-shaped members 66 and 61 are sealed together and to the partition or barrier 64 by means of the bead of glass 65, to provide a hermetically sealed container 63 for receiving a predetermined amount of mercury 10. The ceramic partition or barrier 64 is formed with an eccentrically located cylindrical aperture 1|, the eccentricity being evident in Fig. 3 from the fact that the aperture is located below the center of the partition 64.

The glass bead extends over the adjacent sharp corners 69 of the cup-shaped members suftlciently to retain these cup-shaped members under the depending edges 63h of the glass bead to fasten these parts permanently together.

The amount of mercury 10 in the mercury switch 63 is suiicient so that it fills the lower part of each chamber 12, 13 located on the opposite sides of the partition 64 and extends through theaperture 1| to establish an electrical connection between the terminal members 66 and 61 lens the mercury switch is in the position of The unit is preferably provided with indicia, such as the word Top on the frame 54 at the top of Fig. 1, as indicated at 55 (Fig. 1) and the switch unit is so oriented or rotated in the housing 2| that when the`actuating member 60 is in its upper position, as shown in Fig. 2, with the switch on, as indicated on the actuating member at 56 (Fig. 1) the mercury and barrier are in the full line position of Fig. 3.

Then the two pools of mercury on each side of the barrier 64 in the chambers 12, 13 are in communication with each other through the aperture 1|, as shown in Fig. 3, and the switch is on. When, however, the mercury switch unit is rotated to the dotted line position of Fig. 3, the aperture 1| is in the position shown in dotted lines in Fig. 3, above the two bodies of mercury on either side of the barrier 64, and the barrier cuts oi these two bodies and insulates them from each other, thus protecting the circuit between the two cup-shaped end walls 66, 61 of the mercury switch unit 20.

In order to rotate the mercury switch unit 28 in the housing 2| this unit is preferably provided with a pair of pressed recesses 51, one in each of the metal cups 66, 61, the recesses 51 extending radially inwardly in the cylindrical portions or surfaces 30, 3| on the side which wil1 be toward the top in Figs. 2 and 3.

'Ihe recess 51 may be engaged by a pair of complementary radially projecting lugs 58, 59 carried by the actuating member 60 on the cylindrical inner surfaces 14, 15 (Fig. 6).

The windows 6| may comprise elongated slots located inthe top, bottom, and both sides, or in the projecting partof the actuating member 69 for exposing illumination from the lamp; or these windows may be provided with red, green, or other coloredinserts for changing the characteristics of the light emitted from the handle.

The windows are preferably not placed-'in the end of the actuating member 60, unless the light is suitably dimmed or colored by partially opaque or translucent inserts in the window.

The actuating member 69 is best shown in Figs. 2, 3, 5, 6, 7,- 10, and 11. This member is preferably formed of thermo-plastic material, such as polystyrene, which may be formed by injection methods in a suitable mold.

The actuating member has a handle portion 16, which may be substantially rectangular in cross section, as seen by its end 11 (Fig, v1). The handle portion 16 is integrally attached to a generally cylindrical body portion 18, which has the two cylindrical inner surfaces 14, 15 that engage the cylindrical side walls 30, 3| 0f the mercury switch unit 20.

The cylindrical inner surfaces 14, 15 are shown in spaced relation to the complementary cylindrical surfaces 36, 3| on the mercury switch unit 29 in Fig. '1; and it will be apparent that these cylindrical surfaces 14, 15 on the actuator 60 are spaced from each other by the groove 19, which provides room for the glass bead 65.

In addition to the recess or slot 19 for the glass bead, the actuating member body is provided with a groove 80 at one side of the slot 19 for receiving the electrical resistor 8| and with a cylindrical bore 82 communicating with the resistor groove 88 for receiving a pigtail 83, forming the connection between the lead from the resistor and an adjacent connector member 84, the other connector member being indicated at 85 (Fig. 5).

In addition to the recesses and bores described, the slot 19 communicates with a centrally located bore 84a, which extends longitudinally into the rectangular handle 16 and provides space for receiving the lamp 94. The bore 84a is substantially cylindrical at its inner end, as shown by the smooth surface in the bore 84a in Fig. 5, but at its outer end the b^re is preferably provided with a plurality of inwardly extending integral ribs 86, preferably equiangu larly spaced and of the same shape about the wall of the bore.

Theribs 86 extend longitudinally of the bore and are adapted to engage the side walls of the lamp 94 to hold it in spaced relation to the walls of the bore 84a. In the manufacture of such neon bulbs variations of size and shape inevitablv occur during the manufacture of these devices, which preclude an accurate, nonrattling t between a cylindrical bore and the bulb. The 1ongitudinally extending ribs 86 permit bulbs which vary in their size and shape, due to manufacturing diiiiculties, to be fitted snugly in the cavity 84a under practically all conditions. The three point rib contact can generally be made to t the bulb snugly byrotating the bulb slightly; but, if not, it is a simple matter to scrape oi one of the ribs to provide sufficient space for a snug fit. Such an arrangement is illustrated in section in Fig. 11.

The bore 84a is preferably provided, however, with the light diffusing formations 88 of Fig. 10, which comprise a plurality of cylindrically convex formations 88 on the inside of the bore 84 and extending longitudinally thereof and joined at sharp grooved apices 89.

These cylindrical formations 88 are like cylindrical lenses for diffusing the light from the lamp and preventing glare, while uniformly illumi-` nating the handle member 16.

The body 18 of the actuating memberi may be of the same thickness as the handle portion 16, except that it is preferably provided adjacent the cylindrical surfaces 14, 15 with a pair of laterally projecting curved flanges 90, 9 I, which flanges are provided with partially cylindrical upper surfaces 92 (Fig. 7).

The upper surfaces 92 of these ilanges are adapted to be engaged by a pair of spring wires 93 (Fig. 2), which hold the actuating member resiliently against the mercury switch unit 20, maintaining the projections 58 and 59 on the actuating member 53 in the depressions 51 (Fig. 3), which are located in the cylindrical surfaces 30, 3| of the mercury switch unit 29. This causes the actuating member 69 and the mercury switch unit 20 to rotate as a unit, when the handle 16 is moved upward or downward.

Referring to Fig. 4, this isa view in perspective of the lamp assembly unit, and it comprises a glow lamp 94 of the type comprising a sealed glass envelope 95, from which the air has been evacuated and replaced by a suitable gas, such as argon.

The envelope 95 has a pair of metal leads 96, 91, which pass out of a sealed end portion 98 in the envelope 95 to provide connections for the lamp. The leads 96 and 91 also actas columns in the lamp and carry spaced electrodes 99, ||||1 inside the lamp, which act to provide the illumination by means of the glow of the gas at one or the other of the electrodes or between the electrodes.

Such a lamp can be operated on direct or alternating current, but it requires that initially a greater voltage be applied to break down the initial resistance and light the lamp than the amount of voltage which is later continuously applied to maintain illumination.

Such an energization may be provided by connecting in series with the lamp 94 a very high resistance, such as the resistor 8|, comprising a small cylindrical ceramic body, which is hollowed out and provided with carbon particles in its interior, which are in electrical connection withv w ing material.

7 the resistor 8|, after illumination has been effected.

The lamp 94 is preferably arranged in the handle 16, inside the bore 84a, in such a rotative position that the two leads 96, 91 are located at the same elevation instead of being above or below each other. Thus the jarring of the actuating element 60 can never cause the two leads 96, 91 to come into contact with each other.

In addition to this, the leads 96, 91 are preferably made as short as possible; and one of the leads, such as 91, may extend diagonally in a. transverse direction, as indicated by |03 in Fig. 4, substantially parallel to the resistor 8|.

The lead from the resistor 8| may be bent at slightly more than right angles, as shown in Fig. 3, and twisted with the lead |03 to form the pigtail 83, previously mentioned. This pigtail may-be located in the bore 82, While the lead portion |03 and resistor |0| are located in the slot 30, spaced from all parts of the mercury switch unit 20.

The opposite lead |02 from the resistor |8| may be bent at an obtuse angle so that it is located to be engaged with one of the connectors 84, 85, for example the connector 84. These connectors may be identical in shape, but of different length, as shown in Fig. 4. Each may consist of a substantially T-shaped strip of resilient metal, the top parts of the T being folded over on each other, as indicated at |04 (Fig. 3) to clamp the end portions of the leads |02 and 95.

For this purpose each lead |02 or 95 has its end portion bent at |05 (Fig. 3) into substantially U-shape, the U being substantially as wide as the column of the T-shaped connector strip 85 or 84. The attaching flange portion of each connector strip 84, 85 is indicated in its entirety by the numeral |04, and these attaching flange portions |04 extend spaced from each other and substantially parallel to each other longitudinally oi the lamp 94, extending away from its base.

Each attaching ange portion of the connectors 84, 85 may then be bent outwardly at an obtuse angle at |05 and bent backwardly upon itself at |01, with an easy bend, so that the lower surfaces |08 of each connector are substantially cylindrical, but resilient. These surfaces |08 are adapted to engage the cylindrical surfaces 30, 3| of the mercury switch unit 20, as shown in Fig. 5, while the glass bead 66 is received in the space between the leads 95, 91 at the connector bodies |04.

Thus the flanges |08 of each connector 84, 35 are adapted to be clamped against the cylindrical surfaces 30, 3| of the mercury switch unit by the actuating member 50, which has cylindrical surfaces 14, 15 engaging outside of the connector flanges.

As previously stated, resilient pressure is placed upon the actuating member 60 to hold it in rm engagement with the mercury switch unit by means of the wires 93.

The wires 93 comprise resilient cylindrical members, preferably constructed of material such as Phosphor bronze or other resilient noncorrod- Each wire has an attaching portion H0, at each end, and each attaching portion supports an inwardly extending portion i2, H3, The adjacent straight portions i4, ||5 are joined by a depressed portion ||8, which has at its ends two diagonally extending camming portions Ill, H8.

lThe attaching portions I|0, are welded or soldered to the rear side of the frame member 54, with the wires 93 extending parallel to each 8 other and spaced to engage'ilanges 80, 9| on the actuator 60.

Referring to Fig. 2, it will be seen that the handle member 60 has upon its side flanges a pair of partially cylindrical ridges ||9, |20 (see also Fig. 7), These cylindrical ridges H9, |20 engage the springs 93, and the springs react against the frame 35, which is secured to the housing 2| by the screw bolts 34. Further than this the ridges ||9, |20 serve as retaining members for holding the switch in either of its positions.

This is brought about by the fact that the depressed portion I6 is straight, whereas the rotation of the mercury switch unit 20 and the handle member G0 involves the ridges ||9, |20 moving in an arc on the line of a circle.

As these ridges move against the straight portions |||i of the springs, there is increased re sistance until the ridges H9, |20 pass the midpoint and snap again into the other corner |2|. The corners |2| in the wire facing the mercury switch unit serve as retaining depressions for the ridges ||9, |20, into which the ridges are received as the switch is moved from one position to the other.

The frame 35 also serves to hold the barriers 5|, 52 in place by engaging their left edges in Fig. 2, and the barriers 5|, 52 serve to hold the connectors 42, 43 in position on the housing 2|.

The cover plate |22 (Fig. 2) may be of the same shape as the cover plate upon any toggle switch, having a flat body |23, a rearwardly extending border iiange |24, and a rectangular aperture |25 for passing the switch actuating member 50.

The rectangular aperture |25 is large enough to permit the actuating member 60 to have the desired range of movement, and this aperture exposes the legends On and Off, which are carried by the body member 18 of the switch on the surfaces |26, |21.

The operation of the switch is as follows: The switch must be properly installed upon the wall; and although it may be designed for a vertical wall or a horizontal wall, or other angle, it must be so installed that when the actuating member 60 is in the position of Fig. 3, the bodies of mercury are connected through the aperture 1 I; and when the switch actuating member 60 is moved to the dotted line position, the bodies of mercury in the switch are separated because the aperture 1| is raised to the dotted line position of Fig. 3.

When the switch is in the full line position, that is, the "On position of Fig. 3, the neon bulb is extinguished because the switch shown in the circuit of Fig. 1 is closed. Under these conditions the neon bulb and its resistance are short circuited by the switch. When the actuating member 60 is moved downward in Figs. l, 2, and 3, the ridges H9, |20 move out of the upper corner |2| of the wires 93 until they move downward into the lower corner to hold the switch in the Off position.

During this motion the actuating member B0 by means oi the projections 59 in the depressions 51 of the mercury switch unit 20 cause the mercury switch unit to rotate against the surfaces 21, 28 in the housing until the circuit is broken because the aperture 1| is moved up above the free level of the mercury.

When the circuit is broken at the switch as shown in Fig. 8, this leaves the lamp |23 or other device which the switch is controlling in the circuit with the neon lamp 94 and its resistance 8|.

The neon lamp is thus caused to glow, and it illuminates the switch actuating member 80 so that it can beseen in the dark. This also indicates that the lamp or other device |28 is in good condition, as a broken circuit at the lamp would extinguish the neon lamp also.

While the neon lamp 85 will be illuminated a considerable portion of the time, this illuminating device consumes 'such a small amount of current that its cost will be practically negligible. Furthermore, these neon bulbs have a very long life and may be used for a considerable period of time without replacement.

Replacement of the neon bulb unit shown in Fig. 4, with its resistor and connectors, is also a simple matter, and may be accomplished in a minimum amount of time.

It will thus be observed that I have invented an improved actuating device for electric switches which is adapted to indicate the location of the switch in the dark, to indicate the n or 011m condition ofthe switch and to indicate the condition of the circuit, such as an open circuit caused by the failure of a lamp controlled by the switch.

As there are no moving parts other than the mercury switch unit, whichrotates with the actuating member, there is nothing that can get out of order; and the present switch assembly may be used for an indefinite period oi time without necessity for repair or replacement of any of its parts.

Every part of the unit which exposes any electrades to sparking is hermetically sealed in -rny switch unit, and therefore it may be used wherever there is possibility of explosion of gas by exposed sparking.

'Ihe present actuating members may be manuiactured at a very low cost and may be equipped with neon bulbs already on the market, so that such an actuator may be used upon many different types of switches. As the actuator may be made transparent, translucent, opaque with windows, or provided in different colors, it is readily adaptable for 'use in many different installations, such as homes, commercial, industrial, traiiic control, etc.

The light which is emitted may be suitably diffused sc that there is a control of the brilliancy, which will avoid any glare that might annoy the operator. The parts of the glow lamp l and resistance are suitably supported so that the lamp is ventilated and there are no undue strains placed upon the lamp or on its electrodes or on the resistance member.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, Ibut desire to avail myself of all changes within the scope of the appended claims.

Having thus described -my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric actuating member assembly cornprising a handle member for actuating a switch, said handle member having an elongated projecting body, said body being formed with an internal chamber extending longitudinally of the body, a glow lamp in said chamber and extending longitudinally thereof and supported by the walls of said body, said glow lamp having its terminals protruding at one end of said body for connection to an electric switch device which is to be actuated by said actuating member, said 10 body being formed at said latter end with a transverse enlargement, said enlargement being formed with a chamber portion for receiving a resistor, and a resistor connected to one of the terminals of said glow lamp and located in said chamber portion extending transversely to the glow lamp, said transverse portion of said body being formed with a pair of surfaces for engaging a mercury switch unit, and each of said surfaces being engaged by a connector to be coniined between said surface and the mercury switch unit, one connector being connected to a terminal of the lamp and the other to the free terminal of said resistor, said transverse portion lbeing provided with a pair of laterally projecting ilanges to be engaged by a pair of spring membersfor holding the actuating member and connectors in engagement with said mercury switch unit.

2. A mercury switch unit and actuator assembly comprising a mercury switch member having a pair of metal housing membersV joined by an insulating apertured barrier forming two chambers separated by said barrier and provided with a supply of mercury in said two chambers, an actuating member having-an end portion shaped to engage the metal housing members, and having an outwardly projecting actuating portion, an electric illuminating device in said actuating portion and having electrical conductors extending toward and into engagement with said metal housing members, said conductors being confined between said metal housing members and said actuating member for electrical contacting engagement between the mercury switch unit and the illuminating device.

3. A mercury switch unit and actuator assembly comprising a. mercury switch member having a pair of metal housing members joined by an insulating apertured barrier forming two chambers separated by said barrier and provided with a supply of mercury in said two chambers, an actuating member having an end portion shaped to engage the metal housing members, and having an outwardly projecting actuating portion, an electric illuminating device in said actuating portion and having electrical conductors extending toward and into engagement with said metal housing members, said conductors being confined between said metal housing members and said actuating member for electrical contacting engagement between the mercury switch unit and the illuminating device, said illuminating device comprising a glow lamp and said actuating member being illuminated by saidglow lamp to indicate the open condition of the switch unit when the aperture in the barrier is located above the bodies of mercury.

4., In an electric switch, the combination of an insulating housing provided with a chamber having one open side and having its opposite bottom wall providedwith a pair of partially cylindrical bearing surfaces, a mercury switch unit having cylindrical walls and being operatively mounted in said housing, spring means extending across the opening of said insulating housing, and an actuating member having a' cavity therein for receiving a. member to be controlled by said meru cury switch unit, and having a pair of spaced but aligned partially cylindriical surfaces for engagn ing the mercury switch unit cylindrical walls on a surface opposite to the bearing surfaces on said housing, a controlled electrical device in said actuating member and having leads connected by being pressed between the aligned cylindrical surfaces on said actuating member and the cylindrical walls of the mercury switch unit by said spring means. said actuating member and mercury switch unit being interlocked whereby the actuator is adapted to rotate the switch unit to make or break a circuit.

5. In an electric switch, the combination of an insulating housing provided with a chamber having one open side and having its opposite bottom wall provided with a pair of partially cylindrical bearing surfaces, a mercury switch unit having cylindrical walls and being operatively mounted in said housing, spring means extending across the opening of said insulating housing, and an actuating member having a cavity therein for receiving a member to be controlled by said mercury switch unit, and having a pair of spaced but aligned partially cylindrical surfaces for engaging the mercury switch unit cylindrical walls on a surface opposite to the bearing surfaces on said housing, a controlled electrical device in said actuating member and having leads connected by being pressed between the aligned cylindrical surfaces on said actuating member and the cylindrical walls of the mercury switch unit by said spring means, said actuating member and mercury switch unit being interlocking whereby the actuator is adapted to rotate the switch unit to make or break a circuit, said actuating member having its cavity provided with axially extending spaced ribs for engaging said electrical member, and said electrical member comprising a glow bulb, the light of which is visible through said actuating member, the spaced ribs permitting bulbs of slightly different size, due to manufacturing variations, to be seated securely in said actuating member.

6. In an electric switch, the combination of an insulating housing provided with a chamber having one open side and having its opposite bottom wall provided with a pair of partially cylindrical bearing surfaces, a mercury switch unit having cylindrical walls and being operatively mounted in said housing, spring means extending across the opening of said insulating housing, and an actuating member having a cavity therein for receiving a member to be controlled by said mercury switch unit, and having a pair of spaced but aligned partially cylindrical surfaces for engaging the mercury switch unit cylindrical walls on a surface opposite to the bearing surfaces on said housing, a controlled electrical device in said actuating member and having leads connected by being pressed between the aligned cylindrical surfaces on said actuating member and the cylindrical walls of the mercury switch unit by said spring means, said actuating member and mercury switch unit being interlocked whereby the actuator is adapted to rotate the switch unit to make or break a circuit, the said spring means including a pair of springs, one arranged on each side of said actuating member, and each engaging an opposed surface on said actuating member to press the said leads into rm engagement with the walls of said cup members.

7. In an electric switch, the combination of an insulating housing provided with a chamber having one open side and having its opposite bottom wall provided with a pair of partially cylindrical bearing surfaces, a mercury switch unit having cylindrical walls and being operatively mounted in said housing, spring means extending across the opening of said insulating housing, and an actuating member having a cavity therein for receiving a member to be controlled by said mercury switch unit, and having a pair of spaced but aligned partially cylindricalsurfaces for engaging the mercury switch unit cylindrical Walla on a surface opposite to the bearing surfaces on said housing, a controlled electrical device in said actuating member and having leads connected by being pressed between the aligned cylindrical surfaces on said actuating member and the cylindrical walls of the mercury switch unit by said spring means, said actuating member and mercury switch unit being interlocked whereby the actuator is adapted to rotate the switch unit to make or break a circuit, said actuating member having its cavity formed with a plurality of relatively narrow widely spaced ribs, three in number, for engaging the electrical member, which comprises a glow bulb, to hold the bulb snugly, irrespective of variations in shape and size of the bulb envelope,

8. In an illuminated safety switch, the combination of a supporting insulating housing having bearing surfaces with a mercury switch unit having connector cups with complementary trunnion surfaces movably mounted on the housing, a hollow handle connected to the mercury switch unit for urging the switch unit against such bearing surfaces, and a neon bulb whose light is visible in said handle, controlled by said mercury switch unit, said neon bulb having terminals confined between the handle and being in engagement with said switch unit cups, and resilient spring means carried by the housing and holding said terminals in non-sparking contact with the mercury unit cups, which react against the housing bearing surfaces.

9. In an illuminated safety switch, the combination of an insulating housing having partially cylindrical bearing surfaces, with a mercury switch unit having opposed metallic cups with complementary external cylindrical surfaces mounted for rotation on said bearing surfaces, a hollow handle having a neon bulb in said handle, the light of the bulb being visible through parts of the handle, said handle having flanges for engagement with said cups, connector leads extending from said bulb, and one of said leads being confined between each cup and said flanges, shoulder means carried by the handle flanges engaging depression means i'ri said cups, whereby the handle rotates the switch unit, and resilient means carried by the housing and engaging the outside of the handle flanges and urging the handle anges toward the switch unit, clamping the terminal leads from the neon bulb firmly against the cups at all times to maintain good nonsparking electrical contact between said leads and cups.

JOSEPH F. COURTNEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,081,827 Lohe May 25, 1937 2,101,093 Payne Dec. 7, 1937 2,134,696 Bigman Nov. 1, 1938 2,142,153 Sambleson Jan. 3, 1939 2,142,154 Sarnbleson Jan. 3, 1939 2,214,317 Bash et al Sept. 10, 1940 2,395,698 Tiffany Feb. 26, 1946 

